This disclosure relates to a method for a viewing arrangement, whereby an image is displayed by an image generator, imaged by an optical imaging system, and transmitted to each eye of a viewer via an eyepiece for each eye.
This disclosure also relates to a viewing arrangement comprising image generator, optical imaging system for imaging an image displayed via the image generator and two eyepieces for viewing the image via an eyepiece for each eye.
The phrase “bi-monocular viewing arrangement” is meant as an arrangement that comprises two eyepieces through which a viewer can focus an image that is common to both eyes. By “image” can be meant here both a “real” image in the form of an object or a landscape, and a “created” image on a display screen. Examples of the former are an optical instrument, for example a telescope, a microscope, etc, where a common image is viewed through two eyepieces via a single lens. Such an optical bi-monocular viewing arrangement is known through, for example, U.S. Pat. No. 4,205,894, which describes a pair of binoculars intended to be worn as a mask in front of the face in order to leave the hands free to carry out other tasks than aiming the binoculars.
A problem associated with this is the bulky relay system of various prisms and lenses which is necessary to turn the image the right way round and transmit the image to each eyepiece, but which results in an unwieldy and heavy pair of binoculars. A plurality of such relay systems is known in various embodiments. In addition, lenses and prisms are made of optical quality glass which is manufactured to a high degree of accuracy in order not to distort the image. This makes the optical components expensive to produce, for which reason it is desirable to be able to manufacture instruments with as few expensive optical components as possible.
Examples of viewing arrangements of the latter type, that is comprising one or more display screens, are for example military image intensifier binoculars, so-called night-binoculars, in which at least one image generator and possibly a computer create graphical illustrations such as movable distance scales or cross hairs via a display screen. The graphical illustration is then transmitted to the viewer's eyes together with a light-intensified image of the object or landscape that is observed optically. Compare, for example, U.S. Pat. No. 5,579,165 or SE-B-467 278, both of which describe viewing arrangements comprising very complicated relay systems for transmitting the images to the eyepieces. In the arrangement that is described in U.S. Pat. No. 5,579,165 the most important optical components are in addition duplicated, as the description is only applicable to one of the two monoculars of the binoculars. In order for both eyes to be able to see the same common image simultaneously, the binoculars must therefore either comprise two image displays, two light sources, etc, or else the binoculars must comprise an extensive relay system similar to that in U.S. Pat. No. 4,205,894, which then further complicates the design and makes it considerably more expensive.
A known example of a relay system of the type described above, that is comprising a plurality of prisms and lenses for turning the image the right way round and transmitting the image to each eyepiece, is the prism system, also called Carl-Zeiss binocular eyepiece system, which is described in the publication Mirror and Prism Systems, pages 13–45, and which comprises four different prisms, R1, P1, R2 and Pk, through which the beams of light from the lens are arranged to pass. P1 consists of a right-angled prism which is attached to the end of a rhombic prism R1. The joint between the two prisms, R1, P1, which joint has a semi-reflective coating (half-mirror layer), divides the beams of light from the lens into two separate pencils of beams, one pencil of beams being transmitted to the left eye while the other pencil of beams is transmitted to the right eye. Before they reach the intended eye, the beams that pass through A1 and P1 first pass through an additional rhombic prism A2. The second pencil of beams passes through a compensating prism Pk that has been added to the system in order to even out the difference in length between the different paths through the prisms for the two pencils of beams. In this way, the aberration is the same for both paths.
The replacement of the four prisms with a light-splitting cubic prism and three reflecting mirrors is also known, in order to reduce the amount of prism glass.
In the case where the distance between the eyepieces needs to be adjusted, for example on account of different interpupillary distances in different users of the viewing arrangement, that is the binoculars, etc, the two eyepieces are rotated around the common central axis through the lens.
One of the problems which forms the basis for the present invention is thus that the currently known designs are not able to show a common image that originates from only one source, such as a single image generator or a single lens, to both eyes simultaneously, without a complicated and expensive relay system that takes up a lot of space also having to be arranged inside the binoculars. It can also be seen that such relay systems increase the weight and result in more parts that can malfunction.
A further problem with such a required design is that the distance between the eyepieces must be able to be adjusted in a simple and functionally-suitable way.